Helena weekly herald. [volume] (Helena, Mont.) 1867-1900, 1887-11-17
A THEORY OF SLEEP.
PROFESSOR LEO ERRERA GIVES A
RESUME OF SOME POINTS.

What a Scientist Says a Very I'm
maines-Work and Fatigue-Somnam-
bulism-Kohlschlutte Experiments.
In an address to the Anthropological soci-
ETY. of Brussels, Professor Leo Errera has
given resume of some points in the chemi-
cal theory of sleep. The phenomena of sleep
have in common with other vital functions
the character of periodicity. An examina-
tion of such periodic functions in general
may aid in ascertaining the cause of sleep.
The respiratory rhythm is regulated by the
amount of oxygen and carbonic acid in the
arterial blood. When the blood is charged
with oxygen the respiratory center momen-
tarily suspends activity; but soon the tissues
yield their oxygen to the blood, have it re-
placed by carbonic acid, and the blood thus
modified acts as an excitant to the respiratory
center. Ranke has shown that the fatigue
and recovery Of muscles is due to a similar
alienation of the accumulation and discharge
of certain "fatiguing substances" chief
among which is Tactic acid. An injection of
this acid into fresh muscle renders it incapa-
BILE of work; washing the acid out restores
the activity. ---asssgs
4-.~s~~ SLEEP EXPLAINED.
Cannot sleep be explained by similar
chemical theory? Preyer has extended the
views of Binz, Obersteiner and others (who
all agree in making the accumulation of GER
tain products Of fatigue-ermudungsstoffe-
the cause of sleep) by calling all such fatigu-
ing products Of activity "ponogens." These
accumulate in waking life, are readily oxi-
dizable, and absorb the oxygen intended for
glands, muscles and nerve centers until action
is impossible and sleep sets in. Gradually the
ponogens are destroyed by oxidation, slight
excitetion is sufficient to arouse the centers,
and waking life begins Among the ponogens
Preyer counts Tactic acid as the chief, but the
experimental demonstration of this has been
unsuccessful, and the theory, accordingly,
not generally adopted.
Since these researches Armand Gautier has
found in the human body a series of five or
ganic bases akin to creatine, creatinine and
xanthine, and calls them "leucomaines" and
"ptomaines." The physiological properties
of these substances are narcotic, fatiguing
and sometimes lead to vomiting. This is just
what the chemical theory requires The
periodicity of sleep would be explained by
the conservation of energy being applicable
to all bodily activity; work must be followed
by repair; life is a slow suicide. There is,
moreover, reason to believe that the action or
these leucomaines is a direct one upon the
brain; it is a direct intoxication of the brain
centers
CONSTANT STRUGGLE.
A theory of sleep must take account of
three factors-work, fatigue and sleep. The
chemical theory satisfies these demands. All
work, muscular or cerebral, produces waste
products. These accumulate, make work
more and more difficult; this is fatigue. As
the process continues, the waste products,
notably the leucomaines, intoxicate the higher
nerve centers Gust as a dose of morphine
does), and render them incapable of action;
that is sleep The picture is, however much
more complex There is a constant struggle
against the fatigue, which for a time, by dint
of hard work shown in increased secretions
and so on, may succeed. We probably never
arrive at the extreme limit of work; the sem
sation of fatigue intervenes to prevent such
disaster
Fatigue. as is well known, may extend
from muscle to nerve, and from nerve to
nerve center. We may be very tired from
repeatedly lifting a weight, and not be
sleepy, and may be generally sleepy without
any considerable local fatigue. One is peri
pheral, the other central. As the waste pro-
ducts accumulate in the centers, motion and
sensation become more and more sluggish,
until the time comes when the ordinary
stimulation no longer arouses them, and we
Sleep Partial sleep can be similarly ex-
planned. The centers go to sleep in hie-
rarchical order, the highest serving the most
delicate function going first. In waking, the
reverse is the case; the minor centers may be
asleep while the intellectual centers are
awake In somnambulism the latter may be
asleep while the former are awake
THE DEPTH OF SLEEP.
The depth of sleep, according to this theory,
ought to be proportional to the number of
cortical molecules in combination with the
leucomaines. In the beginning of sleep these
are abundant, the cerebral cells inactive, and
a combination easy. The sleep is deep. Soon
the maximum number of combinations is
reached and sleep is deepest From here on,
the leucomaines are gradually eliminated and
destroyed, and sleep should decrease with
decreasing intensity. Kohlschlutter's ex-
periments on the intensity ofseep, as tested
by the noise necessary to awake the patient,
gives the curve for the intensity o; sleep cor
responding to what we should expect by our
theory Variations in our sleep, caused by
an excess of work, etc., are evidently similar
ly explicable. In short, fatigue j. a poison
for which sleep is the normal antidcte.
This theory maintains Q) that the activity
of all the tissues land primarily OK the two
most active, the nervous and muscuiar) gives
rise to substances more or less allied to
alkaloids, the leucomaines; 2) that these in
duce fatigue and sleep; 81 that on waking, if
the body is rested these substances have dis